1. Technical Field
The present disclosure relates generally to a system and methods for sampling, monitoring, or influencing isolated zones within wells, shafts, pits, or other boreholes. More particularly, the disclosure relates to hydraulically isolating zones within a well, shaft, pit, or other borehole to monitor or influence the conditions therein.
2. Background
Packer systems already known in the art can be typically used to isolate zones of interest within a well. Typically, a packer is an apparatus deployed within a well that, when activated, forms a contact seal with the inner surface of the well to hydraulically isolate portions of the well. Typical packers can be activated once deployed to a selected location by applying mechanical force down a well string to cause the packer seal assembly to expand and thereby contact the well wall, forming a seal. Other typical packers are activated by adding fluid down the well string, riser column, or dedicated tube to create elevated pressures (i.e., greater than static fluid pressure in the well) within the packer, which triggers the packer seal assembly to inflate or expand until it forms a seal with the well wall.
Such packer assemblies are commonly operated at relatively high pressures within well bores, and so such traditional packer assemblies are used with pressurized wellhead systems, having gas pressure added to the hydraulic head of fluid in the system. Pressurized wellhead systems can be difficult to maintain and may be prone to malfunction (such as pressure leaks), which can increase complexity and expense of well monitoring projects. Further, pressurized wellhead systems can be costly to operate because of the added equipment, materials, operation, and safety aspects of transporting and handling pressurized gas.
Other drawbacks also exist in typical packer systems, such as: limitations on the number of sampling lines that can pass through the interior of the riser for the packer system in its usual configuration; difficulties associated with passing tubes through the interior and past protruding port assemblies; and maintaining pressure-tight seals through manifolds at the surface. Leaks at connections between riser sections commonly occur in systems with O-ring seals due to sand grains lodging in grooves, nicks in the O-rings, or slightly out-of-round deformation in components. Such leaks may be difficult to detect until the system is assembled, at which point the leaks would result in costly time-loss for disassembly to locate and fix.
What is needed, therefore, is a simple and low-cost well zone isolation system that can operate at relatively low wellhead pressures, thus utilizing a non-pressurized wellhead system that provides for measurements to be taken in, samples collected from, and/or fluid(s) pumped into isolated zones within the well.